debit an account
Fulfillment, in ad serving and billing, was a constant challenge. Overture asked advertisers, in effect, to give them their credit cards. “We ran it like an ATM,” says Meisel. “They gave us an amount of money and we debited their account.” As growth became exponential, Overture was running an order of magnitude more transactions than a credit card network. Every time an Internet user clicked on a link or ad on a SERP, it was an ad sales transaction. Overture’s bookkeeping was like keeping track not only of all the butterflies in the world but also of how many times they beat their wings. “We had to do it minute by minute,” says Meisel. “Credit card issuers only have to reconcile at the end of the month.”
1. "Overture asked advertisers, in effect, to give them their credit cards." Who exactly is "them' and "their" refer to?
2. “They gave us an amount of money and we debited their account.” What does "debited their account" mean here?